======================================================
WARNING: possible circular locking dependency detected
6.2.0-next-20230303 #1 Not tainted
------------------------------------------------------
syz-executor.6/24137 is trying to acquire lock:
ffff88800fe8e3f8 (&journal->j_checkpoint_mutex){+.+.}-{3:3}, at: __jbd2_log_wait_for_space+0x238/0x4b0

but task is already holding lock:
ffff88800fe8a530 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x1a6/0x640

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (sb_pagefaults){.+.+}-{0:0}:
       ext4_page_mkwrite+0x202/0x1aa0
       do_page_mkwrite+0x1a6/0x640
       __handle_mm_fault+0x11b5/0x31e0
       handle_mm_fault+0x2ce/0xb40
       do_user_addr_fault+0x5ca/0x12e0
       exc_page_fault+0x9c/0x1a0
       asm_exc_page_fault+0x26/0x30

-> #2 (&mm->mmap_lock){++++}-{3:3}:
       internal_get_user_pages_fast+0x13a4/0x2e00
       get_user_pages_fast+0xab/0x100
       __iov_iter_get_pages_alloc+0x2df/0x20f0
       iov_iter_get_pages+0xb0/0x110
       bio_iov_iter_get_pages+0x28a/0x1060
       iomap_dio_bio_iter+0x78e/0x1350
       __iomap_dio_rw+0xe22/0x1ce0
       iomap_dio_rw+0x40/0xa0
       ext4_file_write_iter+0x9ab/0x1950
       vfs_write+0x9b4/0xdc0
       ksys_write+0x12b/0x260
       do_syscall_64+0x3f/0x90
       entry_SYSCALL_64_after_hwframe+0x72/0xdc

-> #1 (&sb->s_type->i_mutex_key#6){++++}-{3:3}:
       down_read+0x3d/0x50
       ext4_bmap+0x52/0x470
       bmap+0xb0/0x130
       jbd2_journal_bmap+0xac/0x1d0
       jbd2_journal_flush+0x87f/0xc90
       __ext4_ioctl+0x9fd/0x4330
       __x64_sys_ioctl+0x19e/0x210
       do_syscall_64+0x3f/0x90
       entry_SYSCALL_64_after_hwframe+0x72/0xdc

-> #0 (&journal->j_checkpoint_mutex){+.+.}-{3:3}:
       __lock_acquire+0x2d56/0x6380
       lock_acquire.part.0+0xea/0x320
       mutex_lock_io_nested+0x149/0x1300
       __jbd2_log_wait_for_space+0x238/0x4b0
       add_transaction_credits+0xa42/0xb80
       start_this_handle+0x3a6/0x14d0
       jbd2__journal_start+0x394/0x6b0
       __ext4_journal_start_sb+0x4c2/0x6f0
       ext4_dirty_inode+0xa5/0x130
       __mark_inode_dirty+0x1aa/0xee0
       generic_update_time+0x21b/0x2b0
       file_update_time+0x22f/0x280
       ext4_page_mkwrite+0x2ed/0x1aa0
       do_page_mkwrite+0x1a6/0x640
       __handle_mm_fault+0x11b5/0x31e0
       handle_mm_fault+0x2ce/0xb40
       do_user_addr_fault+0x5ca/0x12e0
       exc_page_fault+0x9c/0x1a0
       asm_exc_page_fault+0x26/0x30

other info that might help us debug this:

Chain exists of:
  &journal->j_checkpoint_mutex --> &mm->mmap_lock --> sb_pagefaults

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sb_pagefaults);
                               lock(&mm->mmap_lock);
                               lock(sb_pagefaults);
  lock(&journal->j_checkpoint_mutex);

 *** DEADLOCK ***

2 locks held by syz-executor.6/24137:
 #0: ffff888016d3c998 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x4f4/0x12e0
 #1: ffff88800fe8a530 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x1a6/0x640

stack backtrace:
CPU: 1 PID: 24137 Comm: syz-executor.6 Not tainted 6.2.0-next-20230303 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x91/0xf0
 check_noncircular+0x263/0x2e0
 __lock_acquire+0x2d56/0x6380
 lock_acquire.part.0+0xea/0x320
 mutex_lock_io_nested+0x149/0x1300
 __jbd2_log_wait_for_space+0x238/0x4b0
 add_transaction_credits+0xa42/0xb80
 start_this_handle+0x3a6/0x14d0
 jbd2__journal_start+0x394/0x6b0
 __ext4_journal_start_sb+0x4c2/0x6f0
 ext4_dirty_inode+0xa5/0x130
 __mark_inode_dirty+0x1aa/0xee0
 generic_update_time+0x21b/0x2b0
 file_update_time+0x22f/0x280
 ext4_page_mkwrite+0x2ed/0x1aa0
 do_page_mkwrite+0x1a6/0x640
 __handle_mm_fault+0x11b5/0x31e0
 handle_mm_fault+0x2ce/0xb40
 do_user_addr_fault+0x5ca/0x12e0
 exc_page_fault+0x9c/0x1a0
 asm_exc_page_fault+0x26/0x30
RIP: 0033:0x7fb56d6e8673
Code: 5d c3 0f 1f 44 00 00 48 8b 0d 59 ed 0a 01 48 8b 05 4a ed 0a 01 4c 8d 81 00 00 00 01 48 39 c8 72 13 4c 39 c0 73 0e 48 8d 50 04 <89> 38 48 89 15 2c ed 0a 01 c3 52 48 8d 35 77 b7 0b 00 48 89 c2 48
RSP: 002b:00007ffc4e8e3698 EFLAGS: 00010287
RAX: 0000001b2c522000 RBX: 00007fb56d4c2008 RCX: 0000001b2c520000
RDX: 0000001b2c522004 RSI: ffffffff81545e38 RDI: 00000000a78f6b75
RBP: 0000000000000001 R08: 0000001b2d520000 R09: 0000001b2c52127c
R10: 0000000000000b75 R11: 00000000a78f6b79 R12: 000000000000373b
R13: 00007fb56d852000 R14: ffffffff81545e38 R15: 00007fb56d85dff0
 </TASK>
tmpfs: Bad value for 'mpol'